Table 7.

Alanine Tetrapeptide, Energy of the Conformers, RMS Deviations in ϕ_1–3, ψ_1–3 from the Ab Initio Data.

Conformer	Ab Initio a	PFF	OPLS-AA/Lb
1	2.71	3.31/1.0	3.19/4.4
2	2.84	2.87/4.7	3.19/6.5
3	0.00	0.14/7.8	−0.32/8.4
4	4.13	3.85/4.0	4.40/5.8
5	3.88	3.24/16.7	3.14/9.3
6	2.20	0.80/13.9	0.96/12.7
7	5.77	6.91/16.0	5.82/6.6
8	4.16	4.12/47.2	4.83/18.8
9	6.92	7.69/8.8	7.14/8.2
10	6.99	6.69/23.0	7.25/14.2
RMS errorc	—	0.69/19.1d	0.56/10.4

Energies in kcal/mol, angles in degrees.

^aLMP2 cc-pVTZ(-f)//HF6-31G**, ref. 21.

^bRef. 1.

^cPositions of the minima shifted uniformly to achieve the lowest RMS deviation from the ab initio results.

^d12.0° without the “runaway” conformer number 8.